1. Field of Use
This invention relates generally to a track idler recoil spring assembly for the endless track of a crawler type machine, such as a crawler tractor, and to a method for installing and removing the recoil spring thereof.
2. Description of the Prior Art
Some crawler type machines, such as crawler tractors, have an endless track trained around a track sprocket, a track idler and a series of supporting track rollers, all of which are rotatably supported on the tractor track frame. In some cases the track idler is mounted on an idler yoke which, in turn, is mounted for longitudinal sliding movement on the track frame to enable the track idler to move toward the track sprocket upon deflection of the track, as when objects are trapped between the track and the sprocket, the idler or a roller. The longitudinal movement of the idler yoke is resisted by means of a coiled, preloaded compression type recoil spring which is part of a track idler recoil spring assembly. Heretofore, it was the practice to provide the spring assembly for installation on the tractor with the spring already installed therein in preloaded or precompressed condition. Mounting of the spring in the spring assembly during manufacture required a specially adapated press to preload the spring means to maintain the spring compressed in the spring assembly during subsequent storage, handling and shipment of the assembly prior to installation on the vehicle. Because of the extremely high energy stored in the spring, the assembly constituted a potentially dangerous item. Failures in components of the assembly during storage and handling, sometimes attributable to improper materials or improper heat treatment of the bolts or bolt seats, have caused the assembly to literally explode. Furthermore, such preloaded spring assemblies often required special tools, if the assembly or the recoil spring thereof was to be installed on or removed from a vehicle in the field rather than in the factory.